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Urogymnus dalyensis
Urogymnus dalyensis (''Freshwater whipray)' Kingdom: '''Animalia Phylum: Chordata Class: Chondrichthyes Order: Myliobatiformes Family: Dasyatidae Genus: Urogymnus Species: Urogymnus dalyensis Environment: milieu, climate zone, depth range, distribution range: Marine; freshwater; brackish; benthopelagic; depth range 1 - 4 m. Tropical. Distribution: Oceania: Australia. Size, weight, age: Max. length: 1.24 m; weight: ?'; age: '? Short description: The freshwater stingray has an apple-shaped pectoral fin disc approximately as wide as long, with the leading margins almost straight and transverse. The moderately long, obtuse snout is flattened with a pointed tip that projects from the disc. The eyes are small and immediately followed by much larger spiracles. There is a broad, somewhat rectangular curtain of skin between the nares, with a subtly fringed posterior margin. The mouth is gently arched and contains a pair of large papillae near the center and 2–3 much smaller papillae near the corners. There are around 37 upper tooth rows and 45 lower tooth rows; the teeth are small, each with a horizontal ridge and groove, and arranged with a quincunx pattern. The pelvic fins are small, no more than a fifth as long as the disc width. The tail tapers from a narrow base to become thin and whip-like, and measures more or less twice the disc length. There is a single serrated stinging spine on top of the tail; the fin folds are absent. The entire upper surface of the disc is densely covered by small dermal denticles that are heart or oval-shaped around the "shoulders" and become tiny and granular towards the disc margins; there are also around 5 relatively large denticles at the center of the disc. The tail is roughened by denticles above and below, with the largest positioned in a midline row before the spine. The dorsal coloration is a uniform light brown to gray-brown, darkening to blackish past the tail spine. The underside of the disc and tail is white, with dark brown bands around the fin margins; the inner margin of the band is irregular, breaking up into small blotches that reach the belly. This species attains a disc width of 1.24 m (4.1 ft), but most do not exceed 1 m (3.3 ft) across. The freshwater whipray is close in appearance to the much larger giant freshwater stingray, but has a shorter, more obtuse snout and narrower dark ventral bands. The two species also differ in several morphometric and meristic characters. Biology: This benthic species is found mainly in rivers, estuaries and low salinity coastal environments. It feeds mainly on small fishes and prawns, which it actively pursues, even beaching itself to trap prey. Life cycle and mating behavior: ?''' ''Main reference:'' '''Last, P.R. and B.M. Manjaji-Matsumoto, 2008. Himantura dalyensis sp. nov., a new estuarine whipray (Myliobatoidei: Dasyatidae) from Northern Australia. In Last, P.R., White, W.T. & Pogonoski, J.J. (eds.): Descriptions of New Australian Chondrichthyans. CSIRO Marine and Atmospheric Research Paper no. 22. IUCN Red List Status: LEAST CONCERN (''LC)' '''CITES: Not Evaluated CMS: Not Evaluated Threat to humans: Harmless Human uses: FAO. Category:Dasyatidae, Stingrays